Do you ever think about how boring it must be to be trapped on a sheet of postage stamps? Of course not, because you are (we hope) a person with a firm grip on three-dimensional reality. But I do. I like to think of the stamp as a little window on a flat world. The people in there are uncomfortable because they have to sit perfectly still — at least while we are looking at them (thank you Erwin Schrödinger).
If you have an interest in learning about what life might be like in a flat universe there is really only one reliable source: the 1884 novel Flatland: A Romance of Many Dimensions by Edwin Abbott. It is a satirical view of Victorian society written with dry humor, but its genius lies in its ability to help us see in only two dimensions. It also gives a very clear picture of how difficult communication would be for beings in different dimensions — definitely worth thinking about in these days of string theory, dark matter, and dark energy.
(You can read Flatland online here.)